diff --git a/drivers/irqchip/irq-mxs.c b/drivers/irqchip/irq-mxs.c
index 96148a7beba1..eaab5a67e536 100644
--- a/drivers/irqchip/irq-mxs.c
+++ b/drivers/irqchip/irq-mxs.c
@@ -28,18 +28,36 @@
 #include <linux/stmp_device.h>
 #include <asm/exception.h>
 
+/*
+ * this device provide 4 offsets for each register:
+ * 0x0 - plain read write mode
+ * 0x4 - set mode, OR logic.
+ * 0x8 - clr mode, XOR logic.
+ * 0xc - togle mode.
+ */
+#define SET_REG 4
+#define CLR_REG 8
+
 #define HW_ICOLL_VECTOR				0x0000
 #define HW_ICOLL_LEVELACK			0x0010
 #define HW_ICOLL_CTRL				0x0020
 #define HW_ICOLL_STAT_OFFSET			0x0070
-#define HW_ICOLL_INTERRUPTn_SET(n)		(0x0124 + (n) * 0x10)
-#define HW_ICOLL_INTERRUPTn_CLR(n)		(0x0128 + (n) * 0x10)
-#define BM_ICOLL_INTERRUPTn_ENABLE		0x00000004
+#define HW_ICOLL_INTERRUPT0			0x0120
+#define HW_ICOLL_INTERRUPTn(n)			((n) * 0x10)
+#define BM_ICOLL_INTR_ENABLE			BIT(2)
 #define BV_ICOLL_LEVELACK_IRQLEVELACK__LEVEL0	0x1
 
 #define ICOLL_NUM_IRQS		128
 
-static void __iomem *icoll_base;
+struct icoll_priv {
+	void __iomem *vector;
+	void __iomem *levelack;
+	void __iomem *ctrl;
+	void __iomem *stat;
+	void __iomem *intr;
+};
+
+static struct icoll_priv icoll_priv;
 static struct irq_domain *icoll_domain;
 
 static void icoll_ack_irq(struct irq_data *d)
@@ -50,19 +68,19 @@ static void icoll_ack_irq(struct irq_data *d)
 	 * BV_ICOLL_LEVELACK_IRQLEVELACK__LEVEL0 unconditionally.
 	 */
 	__raw_writel(BV_ICOLL_LEVELACK_IRQLEVELACK__LEVEL0,
-			icoll_base + HW_ICOLL_LEVELACK);
+			icoll_priv.levelack);
 }
 
 static void icoll_mask_irq(struct irq_data *d)
 {
-	__raw_writel(BM_ICOLL_INTERRUPTn_ENABLE,
-			icoll_base + HW_ICOLL_INTERRUPTn_CLR(d->hwirq));
+	__raw_writel(BM_ICOLL_INTR_ENABLE,
+			icoll_priv.intr + CLR_REG + HW_ICOLL_INTERRUPTn(d->hwirq));
 }
 
 static void icoll_unmask_irq(struct irq_data *d)
 {
-	__raw_writel(BM_ICOLL_INTERRUPTn_ENABLE,
-			icoll_base + HW_ICOLL_INTERRUPTn_SET(d->hwirq));
+	__raw_writel(BM_ICOLL_INTR_ENABLE,
+			icoll_priv.intr + SET_REG + HW_ICOLL_INTERRUPTn(d->hwirq));
 }
 
 static struct irq_chip mxs_icoll_chip = {
@@ -75,8 +93,8 @@ asmlinkage void __exception_irq_entry icoll_handle_irq(struct pt_regs *regs)
 {
 	u32 irqnr;
 
-	irqnr = __raw_readl(icoll_base + HW_ICOLL_STAT_OFFSET);
-	__raw_writel(irqnr, icoll_base + HW_ICOLL_VECTOR);
+	irqnr = __raw_readl(icoll_priv.stat);
+	__raw_writel(irqnr, icoll_priv.vector);
 	handle_domain_irq(icoll_domain, irqnr, regs);
 }
 
@@ -93,23 +111,45 @@ static const struct irq_domain_ops icoll_irq_domain_ops = {
 	.xlate = irq_domain_xlate_onecell,
 };
 
+static void __init icoll_add_domain(struct device_node *np,
+			  int num)
+{
+	icoll_domain = irq_domain_add_linear(np, num,
+					     &icoll_irq_domain_ops, NULL);
+
+	if (!icoll_domain)
+		panic("%s: unable to create irq domain", np->full_name);
+}
+
+static void __iomem * __init icoll_init_iobase(struct device_node *np)
+{
+	void __iomem *icoll_base;
+
+	icoll_base = of_io_request_and_map(np, 0, np->name);
+	if (!icoll_base)
+		panic("%s: unable to map resource", np->full_name);
+	return icoll_base;
+}
+
 static int __init icoll_of_init(struct device_node *np,
 			  struct device_node *interrupt_parent)
 {
-	icoll_base = of_iomap(np, 0);
-	if (!icoll_base)
-		panic("%s: unable to map resource", np->full_name);
+	void __iomem *icoll_base;
+
+	icoll_base		= icoll_init_iobase(np);
+	icoll_priv.vector	= icoll_base + HW_ICOLL_VECTOR;
+	icoll_priv.levelack	= icoll_base + HW_ICOLL_LEVELACK;
+	icoll_priv.ctrl		= icoll_base + HW_ICOLL_CTRL;
+	icoll_priv.stat		= icoll_base + HW_ICOLL_STAT_OFFSET;
+	icoll_priv.intr		= icoll_base + HW_ICOLL_INTERRUPT0;
 
 	/*
 	 * Interrupt Collector reset, which initializes the priority
 	 * for each irq to level 0.
 	 */
-	stmp_reset_block(icoll_base + HW_ICOLL_CTRL);
+	stmp_reset_block(icoll_priv.ctrl);
 
-	icoll_domain = irq_domain_add_linear(np, ICOLL_NUM_IRQS,
-					     &icoll_irq_domain_ops, NULL);
-	if (!icoll_domain)
-		panic("%s: unable to create irqdomain", np->full_name);
+	icoll_add_domain(np, ICOLL_NUM_IRQS);
 
 	return 0;
 }